1. Field of the Invention
The present invention relates to a disk unit in which an actuator having a head on the top is actuated, while a disk is rotated, so that a position of the head is moved with respect to the disk to perform write and read of data to and from the disk by the head.
2. Description of the Related Art
Hitherto, as memory devices of a computer, there are widely used disk units such as a magnetic disk unit and a magneto-optical disk unit. The disk unit is restricted in a using temperature range to, for example, 5° C.˜55° C. Further, also with respect to the temperature variation of the using environment, a temperature gradient is restricted to be not larger than 20° C. per hour. In this manner, the disk unit is ensured a normal operation in such a manner that a user side of the disk unit pays one's attention with respect to the using environment.
In the explanation of a magnetic disk unit by way of example, the magnetic disk unit is expanded in an application field in view of the fact that a memory capacity is large and read and write are free. For example, the magnetic disk unit is adopted for a car navigation system adopting a GPS (Global Positioning System) as a memory unit for renewal data storage, and is loaded onto a car.
However, for example, in the event that the magnetic disk unit is loaded onto a car, the using environment is greatly changed from that in a room. There is a high possibility that the magnetic disk unit is placed under an extremely low temperature of less than −30° C. and an extremely high temperature of more than 80° C. This involves such a problem that the magnetic disk unit, which is restricted in a using temperature range to 50° C.˜55° C., is no longer usable.